1. Field of the Invention
This invention relates generally to fiber optic cable equipment and, more particularly, to cable terminations for hybrid electrical/fiber optic cables.
2. Description of the Prior Art
In typical applications where optical fibers are used, these fibers are combined with standard electrical wires to create hybrid electrical/fiber optic cables. These hybrid cables provide the optical fibers with the benefit of the electrical wires' relatively greater strength, and provide the further advantage that multiple wires are combined into a single, easily handled cable, thus requiring, e.g., fewer cable penetrations through the walls of a building, fewer wire hangers, and fewer man-hours to run the wires throughout the installation site. In the typical installation, the optical fibers are encased within a flexible, stainless steel “k-tube” which provides further support and protection to the fragile fibers. This k-tube is then encased with the electrical wires inside the hybrid cable.
When it is necessary, however, to terminate the hybrid cable, e.g., at a connection, the optical fibers must be separated from each other and from the electrical wires. A termination apparatus is required to “fan out” the optical fibers from the cable. Terminations of this type of hybrid cable typically include a transition where the optical fiber(s) exit the k-tube and enter protective plastic tube(s); the fibers must “fan out” from the k-tube. In previous terminations, this transition (or fan out) was accomplished by means of heat-shrink tubing and adhesive and the transition was potted with polyurethane in a connector shell.
The development of this invention was prompted by a series of failures wherein one or more optical fibers broke within a hybrid cable termination/connector. The breakage occurred during routine handling of the cable and was caused by movement of the end of the k-tube within the connector. The use of heat shrink tubing and adhesive and potting the termination inside the connector proved inadequate to stabilize the k-tube, which pushed through the potting, thereby causing the optical fibers to break. Before the present invention, there was no effective way to immobilize the k-tube and control the fan out in these hybrid cable terminations.